A. Field of Invention
This invention pertains to a method of manufacturing multilayer discs, such as DVD/CD discs and the like, and more particularly, to a method and apparatus in which the various subassemblies or components of multilayer discs are made and assembled in a continuous manner.
B. Description of the Prior Art
Early optical discs, such as CD discs, were made with only a single information layer which was readable by a laser beam directed through one surface of the disc. Novel techniques were used to extend the capacity of discs. High capacity discs are now available, which may have several information layers, each layer being readable by a laser from one surface of the disc. These high capacity discs are known as DVDs and are available in several flavors, such as DVD-5, DVD-9 and so forth, indicating a nominal capacity of 5 Gb, 9 Gb, etc.
Several types of DVDs are also made that are laser readable on both sides including dual layer DVD/single layer DVD (DVD-14); dual layer DVD/dual layer DVD (DVD-18); Single layer/CD (DVD +); and dual layer DVD/CD. These discs are constructed by making two separate substrates, each substrate having at least one information layer (using either a CD or a DVD format) and then bonding the two substrates together, back to back. However, until now all these types of DVDs could only be made in a batch mode. This operation is slow, labor intensive and therefore expensive.